linux/arch/x86/crypto/poly1305_glue.c
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   1/*
   2 * Poly1305 authenticator algorithm, RFC7539, SIMD glue code
   3 *
   4 * Copyright (C) 2015 Martin Willi
   5 *
   6 * This program is free software; you can redistribute it and/or modify
   7 * it under the terms of the GNU General Public License as published by
   8 * the Free Software Foundation; either version 2 of the License, or
   9 * (at your option) any later version.
  10 */
  11
  12#include <crypto/algapi.h>
  13#include <crypto/internal/hash.h>
  14#include <crypto/poly1305.h>
  15#include <linux/crypto.h>
  16#include <linux/kernel.h>
  17#include <linux/module.h>
  18#include <asm/fpu/api.h>
  19#include <asm/simd.h>
  20
  21struct poly1305_simd_desc_ctx {
  22        struct poly1305_desc_ctx base;
  23        /* derived key u set? */
  24        bool uset;
  25#ifdef CONFIG_AS_AVX2
  26        /* derived keys r^3, r^4 set? */
  27        bool wset;
  28#endif
  29        /* derived Poly1305 key r^2 */
  30        u32 u[5];
  31        /* ... silently appended r^3 and r^4 when using AVX2 */
  32};
  33
  34asmlinkage void poly1305_block_sse2(u32 *h, const u8 *src,
  35                                    const u32 *r, unsigned int blocks);
  36asmlinkage void poly1305_2block_sse2(u32 *h, const u8 *src, const u32 *r,
  37                                     unsigned int blocks, const u32 *u);
  38#ifdef CONFIG_AS_AVX2
  39asmlinkage void poly1305_4block_avx2(u32 *h, const u8 *src, const u32 *r,
  40                                     unsigned int blocks, const u32 *u);
  41static bool poly1305_use_avx2;
  42#endif
  43
  44static int poly1305_simd_init(struct shash_desc *desc)
  45{
  46        struct poly1305_simd_desc_ctx *sctx = shash_desc_ctx(desc);
  47
  48        sctx->uset = false;
  49#ifdef CONFIG_AS_AVX2
  50        sctx->wset = false;
  51#endif
  52
  53        return crypto_poly1305_init(desc);
  54}
  55
  56static void poly1305_simd_mult(u32 *a, const u32 *b)
  57{
  58        u8 m[POLY1305_BLOCK_SIZE];
  59
  60        memset(m, 0, sizeof(m));
  61        /* The poly1305 block function adds a hi-bit to the accumulator which
  62         * we don't need for key multiplication; compensate for it. */
  63        a[4] -= 1 << 24;
  64        poly1305_block_sse2(a, m, b, 1);
  65}
  66
  67static unsigned int poly1305_simd_blocks(struct poly1305_desc_ctx *dctx,
  68                                         const u8 *src, unsigned int srclen)
  69{
  70        struct poly1305_simd_desc_ctx *sctx;
  71        unsigned int blocks, datalen;
  72
  73        BUILD_BUG_ON(offsetof(struct poly1305_simd_desc_ctx, base));
  74        sctx = container_of(dctx, struct poly1305_simd_desc_ctx, base);
  75
  76        if (unlikely(!dctx->sset)) {
  77                datalen = crypto_poly1305_setdesckey(dctx, src, srclen);
  78                src += srclen - datalen;
  79                srclen = datalen;
  80        }
  81
  82#ifdef CONFIG_AS_AVX2
  83        if (poly1305_use_avx2 && srclen >= POLY1305_BLOCK_SIZE * 4) {
  84                if (unlikely(!sctx->wset)) {
  85                        if (!sctx->uset) {
  86                                memcpy(sctx->u, dctx->r, sizeof(sctx->u));
  87                                poly1305_simd_mult(sctx->u, dctx->r);
  88                                sctx->uset = true;
  89                        }
  90                        memcpy(sctx->u + 5, sctx->u, sizeof(sctx->u));
  91                        poly1305_simd_mult(sctx->u + 5, dctx->r);
  92                        memcpy(sctx->u + 10, sctx->u + 5, sizeof(sctx->u));
  93                        poly1305_simd_mult(sctx->u + 10, dctx->r);
  94                        sctx->wset = true;
  95                }
  96                blocks = srclen / (POLY1305_BLOCK_SIZE * 4);
  97                poly1305_4block_avx2(dctx->h, src, dctx->r, blocks, sctx->u);
  98                src += POLY1305_BLOCK_SIZE * 4 * blocks;
  99                srclen -= POLY1305_BLOCK_SIZE * 4 * blocks;
 100        }
 101#endif
 102        if (likely(srclen >= POLY1305_BLOCK_SIZE * 2)) {
 103                if (unlikely(!sctx->uset)) {
 104                        memcpy(sctx->u, dctx->r, sizeof(sctx->u));
 105                        poly1305_simd_mult(sctx->u, dctx->r);
 106                        sctx->uset = true;
 107                }
 108                blocks = srclen / (POLY1305_BLOCK_SIZE * 2);
 109                poly1305_2block_sse2(dctx->h, src, dctx->r, blocks, sctx->u);
 110                src += POLY1305_BLOCK_SIZE * 2 * blocks;
 111                srclen -= POLY1305_BLOCK_SIZE * 2 * blocks;
 112        }
 113        if (srclen >= POLY1305_BLOCK_SIZE) {
 114                poly1305_block_sse2(dctx->h, src, dctx->r, 1);
 115                srclen -= POLY1305_BLOCK_SIZE;
 116        }
 117        return srclen;
 118}
 119
 120static int poly1305_simd_update(struct shash_desc *desc,
 121                                const u8 *src, unsigned int srclen)
 122{
 123        struct poly1305_desc_ctx *dctx = shash_desc_ctx(desc);
 124        unsigned int bytes;
 125
 126        /* kernel_fpu_begin/end is costly, use fallback for small updates */
 127        if (srclen <= 288 || !may_use_simd())
 128                return crypto_poly1305_update(desc, src, srclen);
 129
 130        kernel_fpu_begin();
 131
 132        if (unlikely(dctx->buflen)) {
 133                bytes = min(srclen, POLY1305_BLOCK_SIZE - dctx->buflen);
 134                memcpy(dctx->buf + dctx->buflen, src, bytes);
 135                src += bytes;
 136                srclen -= bytes;
 137                dctx->buflen += bytes;
 138
 139                if (dctx->buflen == POLY1305_BLOCK_SIZE) {
 140                        poly1305_simd_blocks(dctx, dctx->buf,
 141                                             POLY1305_BLOCK_SIZE);
 142                        dctx->buflen = 0;
 143                }
 144        }
 145
 146        if (likely(srclen >= POLY1305_BLOCK_SIZE)) {
 147                bytes = poly1305_simd_blocks(dctx, src, srclen);
 148                src += srclen - bytes;
 149                srclen = bytes;
 150        }
 151
 152        kernel_fpu_end();
 153
 154        if (unlikely(srclen)) {
 155                dctx->buflen = srclen;
 156                memcpy(dctx->buf, src, srclen);
 157        }
 158
 159        return 0;
 160}
 161
 162static struct shash_alg alg = {
 163        .digestsize     = POLY1305_DIGEST_SIZE,
 164        .init           = poly1305_simd_init,
 165        .update         = poly1305_simd_update,
 166        .final          = crypto_poly1305_final,
 167        .descsize       = sizeof(struct poly1305_simd_desc_ctx),
 168        .base           = {
 169                .cra_name               = "poly1305",
 170                .cra_driver_name        = "poly1305-simd",
 171                .cra_priority           = 300,
 172                .cra_flags              = CRYPTO_ALG_TYPE_SHASH,
 173                .cra_blocksize          = POLY1305_BLOCK_SIZE,
 174                .cra_module             = THIS_MODULE,
 175        },
 176};
 177
 178static int __init poly1305_simd_mod_init(void)
 179{
 180        if (!boot_cpu_has(X86_FEATURE_XMM2))
 181                return -ENODEV;
 182
 183#ifdef CONFIG_AS_AVX2
 184        poly1305_use_avx2 = boot_cpu_has(X86_FEATURE_AVX) &&
 185                            boot_cpu_has(X86_FEATURE_AVX2) &&
 186                            cpu_has_xfeatures(XFEATURE_MASK_SSE | XFEATURE_MASK_YMM, NULL);
 187        alg.descsize = sizeof(struct poly1305_simd_desc_ctx);
 188        if (poly1305_use_avx2)
 189                alg.descsize += 10 * sizeof(u32);
 190#endif
 191        return crypto_register_shash(&alg);
 192}
 193
 194static void __exit poly1305_simd_mod_exit(void)
 195{
 196        crypto_unregister_shash(&alg);
 197}
 198
 199module_init(poly1305_simd_mod_init);
 200module_exit(poly1305_simd_mod_exit);
 201
 202MODULE_LICENSE("GPL");
 203MODULE_AUTHOR("Martin Willi <martin@strongswan.org>");
 204MODULE_DESCRIPTION("Poly1305 authenticator");
 205MODULE_ALIAS_CRYPTO("poly1305");
 206MODULE_ALIAS_CRYPTO("poly1305-simd");
 207